Posted
by
Roblimo
on Tuesday March 04, 2014 @04:13PM
from the when-you-positively-absolutely-need-to-keep-your-crypto-key-to-yourself dept.

The QuintessenceLabs website doesn't mince words when it comes to self-promotion. It boasts that they are "The world’s first company to harness the quantum properties of lasers to herald a new generation of data security." InvestCanberra says, "the defense and security policy and procurement centre of Australia is the natural location for large conglomerate defense and security corporations and specialist cyber security, advanced communications and radar, ICT and surveillance businesses alike," and goes on to list QuintessenceLabs as one of several "locally headquartered companies that have grown into internationally successful organizations."

Here's another statement taken from the company's website: "QuintessenceLabs is the first in the world to exploit a new generation of quantum cryptographic technology which enables unbreakable, secure storage and communication of sensitive information through the generation of an ultra-secure cryptographic key." Unbreakable? That's a strong boast. Is it true? And even if it's only partly true, your upper management may call on you to explain (and possibly implement) laser-based quantum security, so you need to know what it is and how it works -- and whether it's something your company (or your client companies) need.

John
Leiseboer:QuintessenceLabs is a cybersecurity defense
company. We basically build products that help you generate keys,
manage keys and do that effectively with a security policy so that
the users of those keys know how to use the keys to meet the
requirements of your workenvironment. Quantum Random Number
Generator is actually something we are very proud of. We started like
back in 2008, as a spinoff out of a research group at a university
where work was being done in the experimental field of quantum
physics, related to quantum key distribution.

As part of
that technology development, we had to develop a whole bunch of
components, including what we call the quantum random number
generator. One of the interesting things about quantum key
distribution, is that you need to have a very very high speed source
of true random numbers. And in developing that particular technology,
the QRNG spun out of that, and we found that there are applications
for that in the commercial world as well as in various military and
defense applications as well. So let’s take a walk around the
booth.

What we are
looking at right here is the concept or the demonstration of a
concept of the extraction of entity from a quantum vacuum state. So
the system here is displaying a laser that is called a coherent
laser. In fact, it is a very finely tuned laser. As it is finely
tuned, it also acts as a carrier of quantum information. The quantum
information that is in fact encoded in this laser is a vacuum state.
Random numbers in other words.That’s because in the
quantum world a vacuum actually does have energy—the
spontaneous creation and destructive energy. The way we can actually
measure that you require an apparatus like this. So we a laser, a
beam splitter, which is splitting the laser beam into two equal
components and then we subtract those. In the classical world, what
that would end up being is a vacuum—nothing. But in the quantum
world, because it is a quantum state that we are actually carrying on
the laser and splitting, we end up with the quantum vacuum energy.

We measure
that by subtracting the laser from itself and then amplifying and
filtering that signal, converting it to a digital signal, and
converting that again into the actual random numbers that ultimately
end up as key material. Obviously this is just a concept. It is
really meant to just show and explain what the basic source of
entropy is. That’s the splitting of that laser to bring the
quantum back in. What we’ve actually implemented is obviously a
little bit more sophisticated and a bit more practical. Over here, we
have a rackmount chassis and towards the rear of the chassis you will
notice that there is a card which has on it an aluminum box with the
label which says QuintessenceLabs. That box has within it the optic
components, so in there, we do have a laser, we have all the beam
splitting components, the photo detectors which convert the light
signal into an electrical current. And we have the subtraction
circuitry that subtracts those two beams that I was talking about
earlier.From the particular box, that very high frequency
RF signal is then taken to some analog processing where we amplify
it, we filter it, we frequency shift it. So it basically allows to
get it into the digital domain. So once we’ve done all that
preprocessing, we then pass the signal to an analog to digital
converter and from there, we then go to a very high speed field
programmable gate array which has internal circuitry just used to
condition that random signal to produce the random numbers with a
uniformdistribution.

There are all
sorts of applications for random numbers. I mean, the most well-known
use for random numbers is to seed a key generator. And keys are
obviously required in cryptography.Whether that be
symmetric keys or asymmetric keys you have to start with some truly
random source somewhere. So that’s one application—a very
common application. Other applications most communications protocols,
secure communications protocols also require some element of
randomness within them. You think of that SSL/TLS the transport layer
security protocol. Every time you need to have a session with that,
you have to generate a symmetric key, you would also probably often
use a block cipher that requires an initialization vector.Usually
that’s done with a random number. But if you are using an
algorithm like DSA digital signature algorithm, part of that
algorithm is the requirement to have a nonce, a random number that
got itself repeated is actually a very good source of a nonce.So
there are many different areas in the security field where you find a
good need for random.

In addition
to that, there are non-security related areas, simulation is a
classic example. So the best most realistic simulations you need to
as closely as possible simulate real world events. Most real world
events have some element of random to them. Think about a tree. Think
about a tree in a forest. Think about the leaves on that tree. Each
individual leaf has some element of random movement. A high speed
good quality random allows you to build simulators of for example,
leaves on trees, which will be used in larger simulations yet again
to give very realistic applications.And I guess the final
there is, all sorts of modeling applications, scientific modeling,
mathematical modeling, modeling of weather, and all those sort of
applications large quantities of good quality random numbers are
essential.

One thing I
didn’t mention is the gaming industry.Of course
they like to bias their random in certain ways. One of the best ways
to bias your random is have a very good filtering function that’s
treated with true random, then apply whatever manipulations you
require, to make sure the output matches what you wanted it. But you
start with a biased source, a bias of even more, you are not going to
necessarily get the bias you want. But true random in, bias it the
way you wish, and the gaming industry can make as much as they like
out of it. We actually started our R&D up around in 2008, and
this is 2014, so I guess the rough guess there is approximately six
years. On that way, we’ve developed many different products
that have been spinoffs of the basic technology. The actual effort
gone of this particular development is probably closer to that two to
two and a half years’ duration involving a team of peak load of
about seven to eight individual engineers.

Not it doesn't. Alice can't differentiate between Bob reading the message and an attacker performing a MITM attack

.This depends on your definition of "quantum crypto".
End-to-end quantum cryptography allows you to know whether your communication has been intercepted. It IS theoretically immune to MITM. Simple quantum key generation or exchange however, may not be.

Right. Alice can differentiate between Bob reading the message and a Man in the Middle interception, because to intercept the message, the man in the middle has to read the quantum bit -- that is, in the photon case, measure the polarization-- and reading it destroys it. The Man in the Middle can't then send on a copy of the quantum bit, because of the quantum no-cloning theorem. She can send a photon polarized in a way identical to the way she read the photon-- but that only works if the receiver, Bob, happens to choose the same polarization to measure that the Man in the Middle chose to measure.

There is, however, a footnote to this. Eve actually can clone the photon (cloning photons is what a laser does). But she can't clone it perfectly-- or, more specifically, she can't be sure that the "cloned" photon is actually a copy of the original, or a spurious ("spontaneous emission") photon that happens to be in the same place. So, if she clones the photon, and measures one copy, and sends the other copy on, this shows up as noise in the signal-- exactly the same as stray light. So, Eve can read some of the message, if she's sufficiently clever, but how much is limited by how much noise the people communicating will accept in the signal without realizing that they are tapped.